Wheel bearing assemblies incorporating sensing arrangements

ABSTRACT

A wheel bearing assembly including inner and outer bearing rings, one of which is intended to rotate and the other of which is intended to remain stationary. The assembly also includes two sets of rolling elements between the rings and in angular contact with tracks defined by the rings. Each set of rolling elements is spaced in the direction of the axis of rotation with each set of rolling elements retained by one of two cages. The assembly further includes a sensing arrangement having at least two annular encoders with alternate north and south magnetic poles and at least two sensors operably associated with the encoders and each serving to provide electrical signals generated by the passage of the poles of the arranged encoder. One of the encoders is mounted on the rotatable one of the bearing rings. The other encoder is mounted on one of the cages and each of the sensors and encoders is disposed axially, between the sets of rolling elements.

PRIORITY INFORMATION

This application is a divisional of U.S. patent application Ser. No.10/850,859, filed on May 21, 2004, all of which is incorporated hereinin its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to vehicle wheel bearing assemblies andmore particularly to such assemblies equipped with sensing arrangementsfor sensing rotary speed or position.

In this field there have been many prior art constructions which can betaken to form the background for the invention. In general, rotarybearings employing sensing arrangements for sensing rotary speed orposition can employ a pre-fabricated annular component made of polymericmaterial containing ferrous material which is treated to form alternatenorth and south magnetic poles, see for example, U.S. Pat. No.5,089,817. Such a component referred to as an encoder can be mounted inthe assembly to cause the magnetic poles to pass alongside a sensor,such as a Hall effect sensor, which generates a pulsed electricalsignal.

2. Description of the Prior Art

An object of the present invention is to provide improved assemblies andsensing arrangements of the aforementioned kind.

Accordingly the present invention provides a wheel bearing assemblycomposed of inner and outer bearing rings, one of which is intended torotate and the other of which is intended to remain stationary, two setsof rolling elements between the rings and in angular contact with tracksdefined by the rings, each set of rolling elements being spaced in thedirection of the axis of rotation with each set of rolling elementsretained by one of two cages and a sensing arrangement composed of atleast two annular encoders with alternate north and south magnetic polesand at least two sensors operably associated with the encoders and eachserving to provide electrical signals generated by the passage of thepoles of the associated encoder; wherein one of the encoders is mountedon the rotatable one of the bearing rings and, the other of the encodersis mounted on one of the cages and each of said sensors and encoders isdisposed axially, between the sets of rolling elements.

The encoder can be mounted on different components of the assembly suchas on one of the cages and on the rotatable bearing ring. This enablesthe signals generated by the sensors to be compared, for example. Theencoders can be orientated with their magnetic poles parallel to therotational axis thus in an axial orientation or radial to this axis thusin a radial orientation or in both axial and radial orientations. Thesensors and encoders may be built into the bearing in a protectedposition between the sets of rolling elements. To locate the sensors usecan be made of a housing or a mounting as described hereinafter.

In other embodiments the sensors and encoders lie outboard of thebearing and the wheel assembly for ease of installation or removal.

A second aspect of the present invention provides a wheel bearingassembly composed of inner and outer bearing rings, one of which isintended to rotate and the other of which is intended to remainstationary, sets of rolling elements between the rings and in angularcontact with tracks defined by the rings, the sets of rolling elementsbeing spaced in the direction of the axis of rotation with each set ofrolling elements retained by a cage and a sensing arrangement composedof at least two annular encoders with alternate north and south magneticpoles and at least two sensors operably associated with the encoders andeach serving to provide electrical signals generated by the passage ofthe poles of the associated encoder; wherein one of the encoders ismounted on the rotatable one of the bearing rings and, the other of theencoders is mounted on one of the cages and wherein the inner bearingring is secured onto a wheel hub, a cover is located on the otherbearing ring to enclose the sensors and is carried by an axial portionof the cover.

The invention may be understood more readily, and various other aspectsand features of the invention may become apparent, from consideration ofthe following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Wheel bearing assemblies embodying the invention will now be described,by way of examples only, with reference to the accompanying drawings,wherein:

FIG. 1 is a schematic sectional side view of a first embodiment of awheel bearing assembly;

FIG. 2 is an enlarged view of part of the assembly shown in FIG. 1;

FIG. 3 is a schematic sectional side view of a second embodiment of awheel bearing assembly;

FIG. 4 is a schematic sectional side view of a third embodiment of awheel bearing assembly,

FIG. 5 is a schematic sectional side view of a fourth embodiment of awheel bearing assembly,

FIG. 6 is a schematic sectional side view of a fifth embodiment of awheel bearing assembly,

FIG. 7 is a schematic sectional side view of a sixth embodiment of awheel bearing assembly,

FIG. 8 is a schematic sectional side view of a seventh embodiment of awheel bearing assembly,

FIG. 9 is a schematic sectional side view of an eighth embodiment of awheel bearing assembly, and

FIG. 10 is a schematic sectional side view of a ninth embodiment of awheel bearing assembly.

DETAILED DESCRIPTION OF THE INVENTION

The construction of the various wheel bearing assemblies 9 illustratedthroughout the accompanying drawings is well known per se and likereference numerals are used to designate the same components.

Referring initially to FIG. 1, there is an inner bearing ring 10, anouter bearing ring 11 and two sets or rows of rolling elements in theform of balls 12 therebetween. The balls 12 make angular contact withrunning tracks 13, 14 in the rings 10, 11. In this assembly, theright-hand or innermost track 14 of the ring 10 is actually formed by aseparate support 15 located in a recess 8 in the inner ring 10. A wheelhub is fixed to or integral with the inner ring 10 and receives a nut 16which locates on the support 15. A detachable pressing fits into anouter projecting region 5 of the outer ring 11 and acts as a cover 6 forthe nut 16. At the opposite left-hand or outermost end regions of therings 10, 11 there is a seal 17. Each set of balls 12 is fitted into acage 18, 19 made of plastics material. As is known, the cages 18, 19maintain separation between the balls 12 and guide the balls 12 makingup each set for progression around the tracks 13, 14. During use, theinner ring 10 rotates with the wheel hub whilst the outer ring 11remains stationary. The balls 12 progressively roll in relation to thetracks 13, 14.

In accordance with the invention, the assembly 9 is equipped with asensing arrangement designed to provide an indication of rotary speed orposition. As shown in FIGS. 1 and 2, the cage 19 has an axial projection20 which extends outwardly towards the other ball set. A firstpre-formed annular encoder 21 with alternate axially-orientated northand south magnetic poles is fitted onto an axial surface 22 of theprojection 20 to confront the inner surface of the outer ring 11. Asecond pre-formed annular encoder 23 with alternate north and southaxially-orientated magnetic poles is fitted onto the inner surface ofthe inner bearing ring 10. The encoders 21, 23 are axially and radiallyoffset in relation to one another. A radial bore 24 in the outer ring 11receives a housing 25. As shown in FIG. 2, the inner end of the housing25 has a stepped profile with end walls 26, 27 offset in the radialdirection. The end walls 26, 27 mount sensors 28, 29 which detect thepassage of the magnetic poles of the encoders 21, 23 and provide pulsedelectrical signals with a repetition frequency depending on the movementof the poles of the encoders 21, 23. The signals are carried on leads30, 31 connected with the sensors 28, 29. The signals from the sensor 28represent the rotary speed of the cage 19 while the signals from thesensor 29 represent the rotary speed of the inner ring 10. The signalscan be used in a variety of ways quite separately and independently orcombined or compared with one another.

FIG. 3 shows a modified form of the sensing arrangement shown in FIGS. 1and 2. In this arrangement, the encoder 23 is mounted on a support ring32 fitted to the inner surface of the inner bearing ring 10 and themagnetic poles of the encoders 22, 23 lie in a common axial plane. Theassociated sensors 28, 29 are likewise orientated in a common axialplane corresponding to the inner surface of the outer ring 11. Thesensors 28, 29 are mounted at the inner end of a bore 24 in the ring 11.The leads 30, 31 are used to support and position the sensors 28, 29 andthese leads 30, 31 emerge from the bore 24.

In the embodiments described and illustrated so far the encoders andsensors 21, 23, 28, 29 are all inboard between the sets of balls 12.

In other constructions the encoders and sensors can be outside thebearing interior. Thus, FIG. 4 shows another sensing arrangement withtwo encoders 21, 23 and two sensors 28, 29. The first encoder 21 isagain located on an axial projection 20 of the cage 19 but in thisembodiment the projection 20 extends outwardly rather than inwardly. Thesecond encoder 23 is mounted on an axial region of a further L-shapedring 33 disposed outside the bearing. A radial region of this ring 33 isclamped by the nut 16 against the support 15. As with the arrangementshown in FIG. 3, the magnetic poles of the encoders 21, 23 lie in acommon axial plane as do the opposed associated sensors 28, 29 which arenow supported on an axial portion 34 of the cover 6.

In the assemblies and arrangements depicted in FIGS. 1 to 4 the encoders21, 23 and the sensors 28, 29 are located predominantly in the axialdisposition. FIGS. 5 and 6 show somewhat different arrangements wherethe encoders 21, 23 and the sensors 28, 29 take a radial disposition.

In the arrangement shown in FIG. 5 the encoder 21 is mounted on anoutermost radial surface 35 of the outer cage 19 so the magnetic polestake a radial orientation. The encoder 23 is here mounted on a planewasher 36 clamped between the nut 16 and the support 15. As can be seen,the encoders 21, 23 are both axially and radially offset. The associatedsensors 28, 29 are likewise axially and radially offset and suspended,for example, by a deformable sleeving surrounding the leads 30, 31 andbent into an L-shape. The sleeving can be secured to the axial portion34 of the cover 6 in any suitable fashion.

FIG. 6 shows another arrangement with the encoders 21, 23 and thesensors 28, 29 all in a radial orientation. In this arrangement, theencoder 21 is supported on the innermost radial end face 35 of the cage18. The encoder 23 confronts the encoder 21 and is radially aligned butaxially offset with respect to the encoder 21. A support ring 39 fitsinto a recess 43 in the inner surface of the inner bearing ring 10 andthe support ring 39 serves to mount the encoder 23. The associatedsensors 28, 29 are again suspended by their leads 30, 31 in the sensorvicinity of the encoders 21, 23. The leads 30, 31 pass through the bore24 in the bearing ring 11. FIG. 7 shows an arrangement where theencoders 21, 23 and the sensors 28, 29 are orientated both radially andaxially. Thus, the encoder 21 is again mounted on the radial surface 35of the cage 18 as is in the embodiment shown in FIG. 5. However, thewasher 36 is now L-shaped with an axial region 37 supporting the encoder23 in an axial orientation generally normal to the orientation of theencoder 21. A tubular housing 25 again secured to the axial portion 34of the cover 6 accommodates the sensors 28, 29. The housing 25 has aradially orientated inner end wall 38 supporting the sensor 28 in thesensing vicinity of the encoder 21 and an axial wall 39 supporting thesensor 29 in the sensing vicinity of the encoder 23.

FIG. 8 depicts a similar arrangement to FIG. 6 but here the shape andmass of the support ring 37 for the encoder 21 is modified. The ring 39is now L-shaped and has an axial flange portion 41 fitted directly tothe inner surface of the inner ring 10 which is no longer provided witha recess.

FIG. 9 is again similar to the arrangement shown in FIG. 8 but here theencoder 21 is fixed to the cage 18 with screws. In this arrangement themounting of the sensors 28, 29 is achieved with the aid of a mountingblock 42. The mounting block 42 has a flange 43 affixed with screws 44to the outer bearing ring 11. A bore 45 in the block 42 is co-axial withthe bore 24 in the ring 11. An elongate carrier 46 extends through thebores 45, 24 and mounts the sensors 28, 29 face-to-face in oppositedirections. A further screw 47 is received in a wall of the block 42 topenetrate the bore 45 and the screw can be used to adjustably locatewith the carrier 46.

In the assemblies and arrangements depicted in the drawings anddescribed hereinbefore there is two encoders and two sensors. In FIG. 10a modified arrangement is depicted which uses three encoders and threesensors. Thus in FIG. 10 a first encoder 21 is mounted on an outer endsurface 35 of the cage 18 and takes a radial orientation. A secondencoder 23 is mounted on the inwardly directed end face 48 of the cage19 in confronting relationship to the encoder 21 and likewise take aradial orientation. The encoders 21, 23 are in radial alignment butspaced apart axially. A third encoder 49 is mounted on a support ring 50fitted in a shallow recess 51 in the inner surface of the inner ring 10.The third encoder 49 takes an axial orientation. The sensors associatedwith the encoders are again supported by a common housing 25 located intheir bore 24 in the outer bearing ring 11. In this case the radiallyorientated sensors 28, 29 associated with the encoders 21, 23 arelocated in an annular ridge portion 52 at the end of the housing 25while a further sensor 53 associated with the third encoder 49 andlocated in an axial orientation is located centrally of the inner end ofthe housing 25 within the end ridge portion 52 and radially offsettherefrom.

1. A wheel bearing assembly composed of inner and outer bearing rings,one of which is intended to rotate and the other of which is intended toremain stationary, sets of rolling elements between the rings and inangular contact with tracks defined by the rings, the sets of rollingelements being spaced in the direction of the axis of rotation with eachset of rolling elements retained by a cage and a sensing arrangementcomposed of at least two annular encoders with alternate north and southmagnetic poles and at least two sensors operably associated with theencoders and each serving to provide electrical signals generated by thepassage of the poles of the associated encoder; wherein one of theencoders is mounted on the rotatable one of the bearing rings and, theother of the encoders is mounted on one of the cages and wherein theinner bearing ring is secured onto a wheel hub, a cover is located onthe outer bearing ring to enclose the sensors which are carried by anaxial portion of the cover.
 2. An assembly according to claim 1 whereinthe inner bearing ring is secured with a nut on to the wheel hub.
 3. Anassembly according to claim 1, wherein each of the sensors and encodersare oriented axially.
 4. An assembly according to claim 1, wherein eachof the sensors and encoders are oriented radially.
 5. An assemblyaccording to claim 1, wherein one pair of associated sensors andencoders is oriented radially and one pair of associated sensors andencoders is oriented axially.